1. Field of the Invention
The present invention relates generally to methods and systems for determining the mass flow rate of a fluid, and more particularly to the operation of mass flow controllers.
2. Discussion of the Related Art
Many industrial processes require precise control of various process fluids. For example, in the semiconductor industries, mass flow controllers are used to precisely measure and control the amount of a process fluid that is introduced to a process chamber. The term fluid is used herein to describe any type of matter in any state that is capable of flow. It is to be understood that the term fluid applies to compressible fluids, such as gases and vapors, to which controlled flow may be of interest.
Rate of Decay (ROD) measurements are a known method used to calibrate a variety of flow measurement devices including those utilized in mass flow controllers.
The disclosed embodiments include a system and method for improving the accuracy of a ROD measurement for real time correction in a mass flow controller by modifying the flow path of a mass flow controller to improve the accuracy for the ROD measurement.